Reference
NFL analytics glossary
Every metric this API returns, with the formula, what it is for, and the specific way people get it wrong. Written from how these are actually computed here, not paraphrased.
How much a single play changed the number of points its team could expect to score next — the closest thing football has to a universal currency.
The share of plays that gained enough to keep the drive on schedule. EPA's blunt, stable cousin.
The chance a team wins from the state the game is in right now.
How often a passer completes throws compared with what the throw itself justified.
How far downfield the ball travelled before it was caught or fell — opportunity, measured before the catch.
The share of his team's offensive or defensive snaps a player was on the field for. The first thing to check before anything else.
Yards a receiver gains once the ball is in his hands, as opposed to the yards the throw travelled.
Seconds from the snap until the ball leaves the quarterback's hand, measured by tracking rather than charted by hand.
The last price a market offered before kickoff, and the most accurate public forecast of a game that exists.
Points scored minus points allowed. A better guide to a team's next game than its record is.
The league's own quarterback formula, built from four rate stats and capped at 158.3.
How much a single play moved a team's chance of winning that specific game — the change in win probability, play by play.